Liberal Leader Couillard accused the Coalition Avenir Quebec leader of having created a financial plan based "hypothesis" rather than fact, while Legault shot back by comparing Couillard to Santa Claus and said his policies resembled those of left-wing Quebec solidaire.

The exchange began with Couillard criticizing Legault's financial plan, which promises to boost health and education spending without raising taxes beyond the level of inflation.

"When there are commitments that literally disappear from the financial framework, that are massively underestimated, we're beyond hypothesis, we are in error," Couillard said in Trois-Rivieres, halfway between Montreal and Quebec City.

Almost 200 kilometres away in Lac-Megantic, Legault criticized his Liberal party rival's "ridiculous" number of big budget promises.

"When we look at all the expenses that have been announced in the last six months, they're getting closer to Quebec solidaire, and they're not doing much to put money back in Quebecers pockets," said Legault, who said his rival's spending earned him the moniker "Santa Claus Couillard."

One of Quebec solidaire's co-spokespeople, however, reacted with humour to Legault's claim that the Liberal party's policies resemble those of her party.

"Our ideas are so popular, it's normal they're trying to copy us!" Manon Masse wrote on social media.

Parti Quebec Leader Jean-Francois Lisee, for his part, engaged in a war of words with B'nai Brith Canada, which had called for one of the party's candidates to resign over her controversial past social media posts.

The Jewish organization accused Michelle Blanc of prejudiced and antisemitic statements, citing a 2007 blog post in which she accused a Hassidic Jewish community of being an "extremist sect," and a 2011 Twitter message in which she wrote she'd "forgotten to celebrate Hitler's birthday yesterday."

Lisee described the Jewish group's demands as "threats" and an "attempt to intimidate" as he once again defended his embattled candidate, who was forced to apologize earlier in the campaign for suggesting that a well-known blogger was a pedophile.

While their verbal exchanges drew attention, the leaders also unrolled a series of promises in the area of health, culture and consumer protection.

Lisee promised to tackle high gas prices through his planned Quebec consumer protection office, which he said would look into price fixing by "gas cartels."

"Every Tuesday or Wednesday, something wrong happens in the gas stations in the Montreal area," he said, referring to predictable early-week price hikes.

"This situation just begs for an inquiry, so that's why it's going to be the first (file)," he said.

Couillard, for his part, pledged to help the province's 1.5 million caregivers by creating a tax credit of up to $2,400 per year to help them renovate their homes to accommodate an elderly person.

Couillard also promised to implement a governmental action plan to help caregivers which would include the development of different respite services for patients.

He estimated his promises will cost $60 million, $40 million of which would be for the credit.

Legault, meanwhile, promised to increase funding to libraries and offer two cultural outings a year to elementary and high school-aged children.

Quebec solidaire focused on environment and agriculture, promising to redirect funds from a trust to pay down public debt to instead be used to tackle climate change and finance green infrastructure.

Speaking in Quebec's Eastern Townships, Masse also introduced an agricultural plan that would boost subsidies to organic producers, support local supplies, and review rules governing pesticide use.

With files from Vicky Fragasso-Marquis in Lac-Megantic, Julien Arsenault in Trois-Rivieres and Melanie Marquis in Quebec City.